The present invention relates to a method of manufacturing a sponge. More particularly, this invention relates to a method of manufacturing a sponge using a casting process. This sponge may be used for medical, cosmetic or general purposes.
Currently, ophthalmic sponges are made by taking a large bun of polyvinyl acetate (PVA) foam or cellulose material and cutting it into the desired thickness. The sponge is washed, dried, compressed, cut and then secured to a handle. The sponge must then be sterilized after it is packaged.
One disadvantage with the present process is that it is very labor intensive, and the multiple cutting and handling steps are expensive. Another disadvantage with the present process is that the multiple cutting steps cause some debris to be left on the sponge, which is referred to in the trade as “float away.” No matter how much effort is made to clean up the sponge, some of the debris from the cutting process remains embedded and has the potential to come loose when the sponge is wetted at the time of use. This creates contamination, which, of course, is undesirable in medical applications. Still further, the float away problem is exacerbated by the final step in the conventional manufacturing process. This is a compression step to help shape the sponge. It deeply embeds some of the dust or float away from the cutting operation into the sponge. Another disadvantage is that even if nearly all of the debris is removed from the finished sponge the cutting process leaves an inherently “rough” surface while a smoother surface is preferred.
To overcome the deficiencies found with conventional methods of manufacturing sponges, a new method that does not create float away and results in a smoother finished surface is needed. This method will avoid cutting entirely so as to avoid producing float away particles.